Welcome to the community!
Depending on the phone you have you can block certain types of calls from the phone itself but you can also have Fido block all outgoing international call from your line and that would be the safest way.
Just note if you have Fido block the calls you will not be able to make any international calls unless you call and have the block removed.
You can contact Fido from any available methods listed here.
We can definitely understand that it's not fun to receive these types of calls and we're doing everything we can to establish a way to block unwanted calls on our network, but, we're just not quite there yet.
You can definitely block the numbers calling you directly from your device. Alternatively, you also have the option of changing your number if you're receiving a large amount of spam/fraud calls.
We also suggest reporting these calls to the Canadian Anti-Fraud Centre.
I hope that helps!